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<a name="GstControlSource"></a><div class="titlepage"></div>
<div class="refnamediv"><table width="100%"><tr>
<td valign="top">
<h2><span class="refentrytitle"><a name="GstControlSource.top_of_page"></a>GstControlSource</span></h2>
<p>GstControlSource — base class for control source sources</p>
</td>
<td class="gallery_image" valign="top" align="right"></td>
</tr></table></div>
<div class="refsect1">
<a name="GstControlSource.functions"></a><h2>Functions</h2>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="functions_return">
<col class="functions_name">
</colgroup>
<tbody>
<tr>
<td class="function_type">
<a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gboolean"><span class="returnvalue">gboolean</span></a>
</td>
<td class="function_name">
<span class="c_punctuation">(</span><a class="link" href="GstControlSource.html#GstControlSourceGetValue" title="GstControlSourceGetValue ()">*GstControlSourceGetValue</a><span class="c_punctuation">)</span> <span class="c_punctuation">()</span>
</td>
</tr>
<tr>
<td class="function_type">
<a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gboolean"><span class="returnvalue">gboolean</span></a>
</td>
<td class="function_name">
<span class="c_punctuation">(</span><a class="link" href="GstControlSource.html#GstControlSourceGetValueArray" title="GstControlSourceGetValueArray ()">*GstControlSourceGetValueArray</a><span class="c_punctuation">)</span> <span class="c_punctuation">()</span>
</td>
</tr>
<tr>
<td class="function_type">
<a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gboolean"><span class="returnvalue">gboolean</span></a>
</td>
<td class="function_name">
<a class="link" href="GstControlSource.html#gst-control-source-get-value" title="gst_control_source_get_value ()">gst_control_source_get_value</a> <span class="c_punctuation">()</span>
</td>
</tr>
<tr>
<td class="function_type">
<a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gboolean"><span class="returnvalue">gboolean</span></a>
</td>
<td class="function_name">
<a class="link" href="GstControlSource.html#gst-control-source-get-value-array" title="gst_control_source_get_value_array ()">gst_control_source_get_value_array</a> <span class="c_punctuation">()</span>
</td>
</tr>
</tbody>
</table></div>
</div>
<div class="refsect1">
<a name="GstControlSource.other"></a><h2>Types and Values</h2>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="name">
<col class="description">
</colgroup>
<tbody>
<tr>
<td class="datatype_keyword"> </td>
<td class="function_name"><a class="link" href="GstControlSource.html#GstValueArray" title="GstValueArray">GstValueArray</a></td>
</tr>
<tr>
<td class="datatype_keyword">struct</td>
<td class="function_name"><a class="link" href="GstControlSource.html#GstControlSource-struct" title="struct GstControlSource">GstControlSource</a></td>
</tr>
<tr>
<td class="datatype_keyword">struct</td>
<td class="function_name"><a class="link" href="GstControlSource.html#GstControlSourceClass" title="struct GstControlSourceClass">GstControlSourceClass</a></td>
</tr>
<tr>
<td class="datatype_keyword">struct</td>
<td class="function_name"><a class="link" href="GstControlSource.html#GstTimedValue" title="struct GstTimedValue">GstTimedValue</a></td>
</tr>
</tbody>
</table></div>
</div>
<div class="refsect1">
<a name="GstControlSource.object-hierarchy"></a><h2>Object Hierarchy</h2>
<pre class="screen">    <a href="/usr/share/gtk-doc/html/gobject/gobject-The-Base-Object-Type.html#GObject-struct">GObject</a>
    <span class="lineart">╰──</span> <a href="/usr/share/gtk-doc/html/gobject/gobject-The-Base-Object-Type.html#GInitiallyUnowned">GInitiallyUnowned</a>
        <span class="lineart">╰──</span> <a class="link" href="GstObject.html" title="GstObject">GstObject</a>
            <span class="lineart">╰──</span> GstControlSource
</pre>
</div>
<div class="refsect1">
<a name="GstControlSource.includes"></a><h2>Includes</h2>
<pre class="synopsis">#include &lt;gst/gst.h&gt;
</pre>
</div>
<div class="refsect1">
<a name="GstControlSource.description"></a><h2>Description</h2>
<p>The <a class="link" href="GstControlSource.html" title="GstControlSource"><span class="type">GstControlSource</span></a> is a base class for control value sources that could
be used to get timestamp-value pairs. A control source essentially is a
function over time.</p>
<p>A <a class="link" href="GstControlSource.html" title="GstControlSource"><span class="type">GstControlSource</span></a> is used by first getting an instance of a specific
control-source, creating a binding for the control-source to the target property
of the element and then adding the binding to the element. The binding will
convert the data types and value range to fit to the bound property.</p>
<p>For implementing a new <a class="link" href="GstControlSource.html" title="GstControlSource"><span class="type">GstControlSource</span></a> one has to implement
<a class="link" href="GstControlSource.html#GstControlSourceGetValue" title="GstControlSourceGetValue ()"><span class="type">GstControlSourceGetValue</span></a> and <a class="link" href="GstControlSource.html#GstControlSourceGetValueArray" title="GstControlSourceGetValueArray ()"><span class="type">GstControlSourceGetValueArray</span></a> functions.
These are then used by <a class="link" href="GstControlSource.html#gst-control-source-get-value" title="gst_control_source_get_value ()"><code class="function">gst_control_source_get_value()</code></a> and
<a class="link" href="GstControlSource.html#gst-control-source-get-value-array" title="gst_control_source_get_value_array ()"><code class="function">gst_control_source_get_value_array()</code></a> to get values for specific timestamps.</p>
</div>
<div class="refsect1">
<a name="GstControlSource.functions_details"></a><h2>Functions</h2>
<div class="refsect2">
<a name="GstControlSourceGetValue"></a><h3>GstControlSourceGetValue ()</h3>
<pre class="programlisting"><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gboolean"><span class="returnvalue">gboolean</span></a>
<span class="c_punctuation">(</span>*GstControlSourceGetValue<span class="c_punctuation">)</span> (<em class="parameter"><code><a class="link" href="GstControlSource.html" title="GstControlSource"><span class="type">GstControlSource</span></a> *self</code></em>,
                             <em class="parameter"><code><a class="link" href="GstClock.html#GstClockTime" title="GstClockTime"><span class="type">GstClockTime</span></a> timestamp</code></em>,
                             <em class="parameter"><code><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gdouble"><span class="type">gdouble</span></a> *value</code></em>);</pre>
<p>Function for returning a value for a given timestamp.</p>
<div class="refsect3">
<a name="GstControlSourceGetValue.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody>
<tr>
<td class="parameter_name"><p>self</p></td>
<td class="parameter_description"><p>the <a class="link" href="GstControlSource.html" title="GstControlSource"><span class="type">GstControlSource</span></a> instance</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>timestamp</p></td>
<td class="parameter_description"><p>timestamp for which a value should be calculated</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>value</p></td>
<td class="parameter_description"><p>a value which will be set to the result.</p></td>
<td class="parameter_annotations"> </td>
</tr>
</tbody>
</table></div>
</div>
<div class="refsect3">
<a name="GstControlSourceGetValue.returns"></a><h4>Returns</h4>
<p> <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a> if the value was successfully calculated.</p>
</div>
</div>
<hr>
<div class="refsect2">
<a name="GstControlSourceGetValueArray"></a><h3>GstControlSourceGetValueArray ()</h3>
<pre class="programlisting"><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gboolean"><span class="returnvalue">gboolean</span></a>
<span class="c_punctuation">(</span>*GstControlSourceGetValueArray<span class="c_punctuation">)</span> (<em class="parameter"><code><a class="link" href="GstControlSource.html" title="GstControlSource"><span class="type">GstControlSource</span></a> *self</code></em>,
                                  <em class="parameter"><code><a class="link" href="GstClock.html#GstClockTime" title="GstClockTime"><span class="type">GstClockTime</span></a> timestamp</code></em>,
                                  <em class="parameter"><code><a class="link" href="GstClock.html#GstClockTime" title="GstClockTime"><span class="type">GstClockTime</span></a> interval</code></em>,
                                  <em class="parameter"><code><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#guint"><span class="type">guint</span></a> n_values</code></em>,
                                  <em class="parameter"><code><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gdouble"><span class="type">gdouble</span></a> *values</code></em>);</pre>
<p>Function for returning an array of values for starting at a given timestamp.</p>
<div class="refsect3">
<a name="GstControlSourceGetValueArray.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody>
<tr>
<td class="parameter_name"><p>self</p></td>
<td class="parameter_description"><p>the <a class="link" href="GstControlSource.html" title="GstControlSource"><span class="type">GstControlSource</span></a> instance</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>timestamp</p></td>
<td class="parameter_description"><p>timestamp for which a value should be calculated</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>interval</p></td>
<td class="parameter_description"><p>the time spacing between subsequent values</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>n_values</p></td>
<td class="parameter_description"><p>the number of values</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>values</p></td>
<td class="parameter_description"><p>array to put control-values in</p></td>
<td class="parameter_annotations"> </td>
</tr>
</tbody>
</table></div>
</div>
<div class="refsect3">
<a name="GstControlSourceGetValueArray.returns"></a><h4>Returns</h4>
<p> <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a> if the values were successfully calculated.</p>
</div>
</div>
<hr>
<div class="refsect2">
<a name="gst-control-source-get-value"></a><h3>gst_control_source_get_value ()</h3>
<pre class="programlisting"><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gboolean"><span class="returnvalue">gboolean</span></a>
gst_control_source_get_value (<em class="parameter"><code><a class="link" href="GstControlSource.html" title="GstControlSource"><span class="type">GstControlSource</span></a> *self</code></em>,
                              <em class="parameter"><code><a class="link" href="GstClock.html#GstClockTime" title="GstClockTime"><span class="type">GstClockTime</span></a> timestamp</code></em>,
                              <em class="parameter"><code><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gdouble"><span class="type">gdouble</span></a> *value</code></em>);</pre>
<p>Gets the value for this <a class="link" href="GstControlSource.html" title="GstControlSource"><span class="type">GstControlSource</span></a> at a given timestamp.</p>
<p><span class="annotation">[<acronym title="This is a method"><span class="acronym">method</span></acronym>]</span></p>
<div class="refsect3">
<a name="gst-control-source-get-value.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody>
<tr>
<td class="parameter_name"><p>self</p></td>
<td class="parameter_description"><p>the <a class="link" href="GstControlSource.html" title="GstControlSource"><span class="type">GstControlSource</span></a> object</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>timestamp</p></td>
<td class="parameter_description"><p>the time for which the value should be returned</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>value</p></td>
<td class="parameter_description"><p>the value. </p></td>
<td class="parameter_annotations"><span class="annotation">[<acronym title="Parameter for returning results. Default is transfer full."><span class="acronym">out</span></acronym>]</span></td>
</tr>
</tbody>
</table></div>
</div>
<div class="refsect3">
<a name="gst-control-source-get-value.returns"></a><h4>Returns</h4>
<p> <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#FALSE:CAPS"><code class="literal">FALSE</code></a> if the value couldn't be returned, <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a> otherwise.</p>
</div>
</div>
<hr>
<div class="refsect2">
<a name="gst-control-source-get-value-array"></a><h3>gst_control_source_get_value_array ()</h3>
<pre class="programlisting"><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gboolean"><span class="returnvalue">gboolean</span></a>
gst_control_source_get_value_array (<em class="parameter"><code><a class="link" href="GstControlSource.html" title="GstControlSource"><span class="type">GstControlSource</span></a> *self</code></em>,
                                    <em class="parameter"><code><a class="link" href="GstClock.html#GstClockTime" title="GstClockTime"><span class="type">GstClockTime</span></a> timestamp</code></em>,
                                    <em class="parameter"><code><a class="link" href="GstClock.html#GstClockTime" title="GstClockTime"><span class="type">GstClockTime</span></a> interval</code></em>,
                                    <em class="parameter"><code><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#guint"><span class="type">guint</span></a> n_values</code></em>,
                                    <em class="parameter"><code><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gdouble"><span class="type">gdouble</span></a> *values</code></em>);</pre>
<p>Gets an array of values for for this <a class="link" href="GstControlSource.html" title="GstControlSource"><span class="type">GstControlSource</span></a>. Values that are
undefined contain NANs.</p>
<p><span class="annotation">[<acronym title="This is a method"><span class="acronym">method</span></acronym>]</span></p>
<div class="refsect3">
<a name="gst-control-source-get-value-array.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody>
<tr>
<td class="parameter_name"><p>self</p></td>
<td class="parameter_description"><p>the <a class="link" href="GstControlSource.html" title="GstControlSource"><span class="type">GstControlSource</span></a> object</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>timestamp</p></td>
<td class="parameter_description"><p>the first timestamp</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>interval</p></td>
<td class="parameter_description"><p>the time steps</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>n_values</p></td>
<td class="parameter_description"><p>the number of values to fetch</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>values</p></td>
<td class="parameter_description"><p>array to put control-values in. </p></td>
<td class="parameter_annotations"><span class="annotation">[<acronym title="Parameter points to an array of items."><span class="acronym">array</span></acronym> length=n_values]</span></td>
</tr>
</tbody>
</table></div>
</div>
<div class="refsect3">
<a name="gst-control-source-get-value-array.returns"></a><h4>Returns</h4>
<p> <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a> if the given array could be filled, <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#FALSE:CAPS"><code class="literal">FALSE</code></a> otherwise</p>
</div>
</div>
</div>
<div class="refsect1">
<a name="GstControlSource.other_details"></a><h2>Types and Values</h2>
<div class="refsect2">
<a name="GstValueArray"></a><h3>GstValueArray</h3>
<pre class="programlisting">typedef struct _GstValueArray GstValueArray;</pre>
</div>
<hr>
<div class="refsect2">
<a name="GstControlSource-struct"></a><h3>struct GstControlSource</h3>
<pre class="programlisting">struct GstControlSource {
  GstControlSourceGetValue get_value;             /* Returns the value for a property at a given timestamp */
  GstControlSourceGetValueArray get_value_array;  /* Returns values for a property in a given timespan */
};
</pre>
<p>The instance structure of <a class="link" href="GstControlSource.html" title="GstControlSource"><span class="type">GstControlSource</span></a>.</p>
<div class="refsect3">
<a name="GstControlSource.members"></a><h4>Members</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="300px" class="struct_members_name">
<col class="struct_members_description">
<col width="200px" class="struct_members_annotations">
</colgroup>
<tbody>
<tr>
<td class="struct_member_name"><p><a class="link" href="GstControlSource.html#GstControlSourceGetValue" title="GstControlSourceGetValue ()"><span class="type">GstControlSourceGetValue</span></a> <em class="structfield"><code><a name="GstControlSource-struct.get-value"></a>get_value</code></em>;</p></td>
<td class="struct_member_description"><p>Function for returning a value for a given timestamp</p></td>
<td class="struct_member_annotations"> </td>
</tr>
<tr>
<td class="struct_member_name"><p><a class="link" href="GstControlSource.html#GstControlSourceGetValueArray" title="GstControlSourceGetValueArray ()"><span class="type">GstControlSourceGetValueArray</span></a> <em class="structfield"><code><a name="GstControlSource-struct.get-value-array"></a>get_value_array</code></em>;</p></td>
<td class="struct_member_description"><p>Function for returning a values array for a given timestamp</p></td>
<td class="struct_member_annotations"> </td>
</tr>
</tbody>
</table></div>
</div>
</div>
<hr>
<div class="refsect2">
<a name="GstControlSourceClass"></a><h3>struct GstControlSourceClass</h3>
<pre class="programlisting">struct GstControlSourceClass {
  GstObjectClass parent_class;
};
</pre>
<p>The class structure of <a class="link" href="GstControlSource.html" title="GstControlSource"><span class="type">GstControlSource</span></a>.</p>
<div class="refsect3">
<a name="GstControlSourceClass.members"></a><h4>Members</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="300px" class="struct_members_name">
<col class="struct_members_description">
<col width="200px" class="struct_members_annotations">
</colgroup>
<tbody></tbody>
</table></div>
</div>
</div>
<hr>
<div class="refsect2">
<a name="GstTimedValue"></a><h3>struct GstTimedValue</h3>
<pre class="programlisting">struct GstTimedValue {
  GstClockTime timestamp;
  gdouble      value;
};
</pre>
<p>Structure for saving a timestamp and a value.</p>
<div class="refsect3">
<a name="GstTimedValue.members"></a><h4>Members</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="300px" class="struct_members_name">
<col class="struct_members_description">
<col width="200px" class="struct_members_annotations">
</colgroup>
<tbody>
<tr>
<td class="struct_member_name"><p><a class="link" href="GstClock.html#GstClockTime" title="GstClockTime"><span class="type">GstClockTime</span></a> <em class="structfield"><code><a name="GstTimedValue.timestamp"></a>timestamp</code></em>;</p></td>
<td class="struct_member_description"><p>timestamp of the value change</p></td>
<td class="struct_member_annotations"> </td>
</tr>
<tr>
<td class="struct_member_name"><p><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gdouble"><span class="type">gdouble</span></a> <em class="structfield"><code><a name="GstTimedValue.value"></a>value</code></em>;</p></td>
<td class="struct_member_description"><p>the corresponding value</p></td>
<td class="struct_member_annotations"> </td>
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